The present invention relates to a foldable handy phone.
It is a common practice with a foldable handy phone to hinge a receiver case and a transmitter case to each other. The receiver case accommodates a speaker or similar sounding means. A through hole is formed in the surface of the receiver case that faces the transmitter case when the handy phone is folded up. The through hole is communicated to the portion of the receiver case accommodating the sounding means.
The user of the above handy phone holds the open end of the through hole or earpiece portion to the ear in order to hear voice output from the sounding means. The maximum sound pressure level (SPL) to be output from the sounding means confined in a hermetic space is limited to about 120 dB or below in order to protect the ear drum from damage. It has been customary to dispose a ringer in either one of the receiver case and transmitter case independently of the sounding means. In the event of a call incoming, the ringer is driven to generate an alert tone for alerting the user to the call.
However, the handy phone equipped with the ringer in addition to the sounding means is large size, heavy weight, and high cost. In light of this, a sensor may be built in the earpiece portion for sensing the distance between the ear and the earpiece portion, so that the sounding means can output an alert tone with a greater volume when the above distance is great, as proposed in the past. Alternatively, the sounding means may function as a speaker at the same time to allow the user to converse without bringing the handy phone closer to the ear, as also proposed in the past.
A clearance more or less exists between the earpiece portion and the ear. The size of the clearance depends on the person, i.e., the shape of the ear and how tightly the earpiece contacts the ear. As the clearance and therefore the degree of sound leak increases, sound pressure in the low pitch range falls due to the variation of the acoustic characteristic, resulting in the noticeable variation of sound quality.
Japanese Patent Laid-Open Publication No. 10-304036, for example, teaches a preleak portion for reducing the above variation of sound quality and always implementing sound easy to hear for all persons. The preleak portion is provided in the earpiece portion for adequately causing sound to leak beforehand. With the preleak portion, it is possible to reduce the influence of the distance between the earpiece portion and the ear.
The sounding means assigned to conversation, but bifunctioning as alert tone generating means, obviates the need for a ringer. This kind of sounding means, however, must be accompanied by the sensor responsive to the distance between the earpiece portion and the ear, increasing the size, weight and cost of the handy phone.
The preleak scheme successfully reduces the variation of sound quality by causing sound to leak beforehand. However, some structure should preferably serve as the preleak portion at the same time in order to obviate the need for the preleak portion.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication No. 3-162025 and Japanese Patent No. 2,570,149.
It is therefore an object of the present invention to provide a small size, light weight and low cost foldable handy phone.
It is another object of the present invention to provide a foldable handy phone including sounding means for conversation capable of bifunctioning as a ringer.
It is a further object of the present invention to provide a foldable handy phone causing sound to adequately leak and thereby stabilizing sound quality.
A foldable handy phone of the present invention includes a receiver case, a transmitter case hinged at one end thereof to one end of the receiver case, and a sounding device disposed in the receiver case. A through hole is formed in the surface of the receiver case that faces the transmitter case when the receiver case and transmitter case are folded. The through hole is communicated to a portion accommodating the sounding device. A groove is formed in the surface of the receiver case and extends from the open end of the through hole to the other end of the receiver case.
The above groove may be replaced with a second through hole also formed in the receiver case and extending from the portion accommodating the sounding device to the other end of the receiver case.